diff -r 000000000000 -r 6474c204b198 testing/mozbase/mozprofile/tests/test_nonce.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/testing/mozbase/mozprofile/tests/test_nonce.py	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,47 @@
+#!/usr/bin/env python
+
+"""
+test nonce in prefs delimeters
+see https://bugzilla.mozilla.org/show_bug.cgi?id=722804
+"""
+
+import os
+import tempfile
+import time
+import unittest
+from mozprofile.prefs import Preferences
+from mozprofile.profile import Profile
+
+class PreferencesNonceTest(unittest.TestCase):
+
+    def test_nonce(self):
+
+        # make a profile with one preference
+        path = tempfile.mktemp()
+        profile = Profile(path,
+                          preferences={'foo': 'bar'},
+                          restore=False)
+        user_js = os.path.join(profile.profile, 'user.js')
+        self.assertTrue(os.path.exists(user_js))
+
+        # ensure the preference is correct
+        prefs = Preferences.read_prefs(user_js)
+        self.assertEqual(dict(prefs), {'foo': 'bar'})
+
+        del profile
+
+        # augment the profile with a second preference
+        profile = Profile(path,
+                          preferences={'fleem': 'baz'},
+                          restore=True)
+        prefs = Preferences.read_prefs(user_js)
+        self.assertEqual(dict(prefs), {'foo': 'bar', 'fleem': 'baz'})
+
+        # cleanup the profile;
+        # this should remove the new preferences but not the old
+        profile.cleanup()
+        prefs = Preferences.read_prefs(user_js)
+        self.assertEqual(dict(prefs), {'foo': 'bar'})
+
+if __name__ == '__main__':
+    unittest.main()